The present invention relates to a hemodialysis use adjunctive device partly implanted in the body for hemodialysis.
As disclosed in the description and drawings of U.S. Pat. No. 4,417,888, for example, this type of hemodialysis use adjunctive device is generally known which comprises an artificial blood vessel to be transplanted in the body at a location between an artery and a vein, such as, for example, between a brachial artery and a brachial vein, a T-shaped tubular body comprising a straight tube portion and a stem portion and interposed in the artificial blood vessel, and an access tube provided at one end thereof with a jack having a pair of needles and is used for hemodialysis by performing the step that the tubular body is transplanted in the human body together with the artificial blood vessel in the state of the stem portion being exposed at its top end portion from the body and then, at the time of hemodialysis, the jack of the access tube is connected to the stem portion of the tubular body and the other end portion of the access tube is connected to a hemodialysis machine.
However, this conventional type one has the problem that when the artificial blood vessel and the tubular body, serving as the hemodialysis use adjunctive device, are transplanted in the body, a blood flow is increased in the vein into which the blood flows through the artificial blood vessel, so that an increased hydrodynamic stress (or rather, an increased shearing stress) acts on the blood vessel wall of the vein, from which internal membrane thickening results, then ending up in stricture or obstruction. This problem is caused not only when the hemodialysis use adjunctive device is transplanted in the body but also when an anastomosis between an artery and a vein is made to enlarge the vein for the facilitation of the hemodialysis.
In order to solve this problem, the inventor of this application previously proposed that a blood stream adjuster having a throttling portion for controlling the blood stream is fitted in the artificial blood vessel (Cf. Description and drawings of U.S. Pat. No. 5,755,779). However, since it is necessary for the blood flow of the order of 60-600 ml/min to flow through the artificial blood vessel of the hemodialysis use adjunctive device during the hemodialysis, this proposed blood stream adjuster cannot be fitted in the artificial blood vessel simply.